[andersmurphy]

> Generalization breaks down for offline-capable applications. Offline writes require conflict resolution, create authorization edge cases, and demand coordinated schema management across server and client replicas.

> ...These constraints are structural; engineering effort cannot remove them...

> The trade-off analysis shows that three sync engine vendors converged independently on this conclusion from different starting positions.

This is the big irony. That the vendors all converged on the fact that sync engines only really "work" when you remove the offline part. But, at that point they are a complicated/over engineered cache or worse introducing hard distributed computer science problems unnecessarily.